CN109923678B - Schottky barrier diode and electronic circuit provided with same - Google Patents

Schottky barrier diode and electronic circuit provided with same Download PDF

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Publication number
CN109923678B
CN109923678B CN201780068998.0A CN201780068998A CN109923678B CN 109923678 B CN109923678 B CN 109923678B CN 201780068998 A CN201780068998 A CN 201780068998A CN 109923678 B CN109923678 B CN 109923678B
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recess
semiconductor substrate
schottky barrier
barrier diode
concave portion
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CN109923678A (en
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平林润
松尾裕
藤田实
有马润
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TDK Corp
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TDK Corp
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    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/86—Types of semiconductor device ; Multistep manufacturing processes therefor controllable only by variation of the electric current supplied, or only the electric potential applied, to one or more of the electrodes carrying the current to be rectified, amplified, oscillated or switched
    • H01L29/861—Diodes
    • H01L29/872—Schottky diodes
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    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
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    • H01L21/02365—Forming inorganic semiconducting materials on a substrate
    • H01L21/02612—Formation types
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    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/28—Manufacture of electrodes on semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/268
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    • H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
    • H01L29/06—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions
    • H01L29/0657—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions characterised by the shape of the body
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    • H01L29/24—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only semiconductor materials not provided for in groups H01L29/16, H01L29/18, H01L29/20, H01L29/22
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    • H01L29/40—Electrodes ; Multistep manufacturing processes therefor
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    • H01L29/40—Electrodes ; Multistep manufacturing processes therefor
    • H01L29/41—Electrodes ; Multistep manufacturing processes therefor characterised by their shape, relative sizes or dispositions
    • H01L29/417—Electrodes ; Multistep manufacturing processes therefor characterised by their shape, relative sizes or dispositions carrying the current to be rectified, amplified or switched
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    • H01L29/40—Electrodes ; Multistep manufacturing processes therefor
    • H01L29/43—Electrodes ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
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    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/73—Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
    • H01L2224/732—Location after the connecting process
    • H01L2224/73251—Location after the connecting process on different surfaces
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    • H01L2924/10—Details of semiconductor or other solid state devices to be connected
    • H01L2924/1015—Shape
    • H01L2924/10155—Shape being other than a cuboid
    • H01L2924/10158—Shape being other than a cuboid at the passive surface

Abstract

The invention provides a Schottky barrier diode using gallium oxide, which can suppress heat generation and improve heat dissipation while ensuring mechanical strength and operability of the Schottky barrier diode. The solution to the problem is: the invention comprises the following steps: a semiconductor substrate (20) made of gallium oxide, which is provided with a recess (23) on the second surface (22) side; an epitaxial layer (30) made of gallium oxide, provided on the first surface (21) of the semiconductor substrate; an anode electrode (40) which is provided at a position overlapping the recess (23) when viewed in the stacking direction, and which is in Schottky contact with the epitaxial layer (30); and a cathode electrode (50) which is provided in the recess (23) of the semiconductor substrate (20) and which is in ohmic contact with the semiconductor substrate (20). According to the present invention, since the thickness of the portion through which the forward current flows is selectively reduced, heat generation can be reduced and heat dissipation can be improved while mechanical strength and operability are ensured. Therefore, the temperature rise of the element can be suppressed even if gallium oxide having low thermal conductivity is used.

Description

Schottky barrier diode and electronic circuit provided with same
Technical Field
The present invention relates to a schottky barrier diode and an electronic circuit provided with the schottky barrier diode, and more particularly, to a schottky barrier diode using gallium oxide and an electronic circuit provided with the schottky barrier diode.
Background
The schottky barrier diode is a rectifying element using a schottky barrier generated by junction between a metal and a semiconductor, and has characteristics of a low forward voltage and a high switching speed as compared with a general diode having a PN junction. Therefore, the schottky barrier diode is sometimes used as a switching element for a power device.
When a schottky barrier diode is used as a switching element for a power device, it is necessary to secure a sufficient reverse breakdown voltage, and therefore, instead of silicon (Si), silicon carbide (SiC), gallium nitride (GaN), or gallium oxide (Ga) having a larger band gap may be used 2 O 3 ) And the like. Among them, gallium oxide has a very large band gap of 4.8 to 4.9eV and a large dielectric breakdown field of 7 to 8MV/cm, and thus a schottky barrier diode using gallium oxide is very promising as a switching element for a power device. An example of a schottky barrier diode using gallium oxide is described in patent document 1.
However, gallium oxide has a considerably lower thermal conductivity than silicon (Si), silicon carbide (SiC), gallium nitride (GaN), and the like. Therefore, when a schottky barrier diode using gallium oxide is used as a switching element for a power device, there is a problem that heat generated by a forward current cannot be efficiently dissipated to the outside of the element, and the element is easily deteriorated. In this regard, the schottky barrier diode described in patent document 1 suppresses heat generation by a forward current and improves heat dissipation by reducing the thickness of the gallium oxide substrate to 50 μm or less.
Documents of the prior art
Patent literature
Patent document 1: japanese patent laid-open publication No. 2016-031953
Disclosure of Invention
Technical problem to be solved by the invention
However, when the gallium oxide substrate is simply thinned, there arises a problem that not only the mechanical strength of the device is insufficient, but also handling (handling) of the device during manufacturing and mounting becomes difficult.
Accordingly, an object of the present invention is to provide a schottky barrier diode using gallium oxide, which can suppress heat generation and improve heat dissipation while ensuring mechanical strength and operability.
Means for solving the problems
The schottky barrier diode of the present invention is characterized by comprising: a semiconductor substrate made of gallium oxide, having a first surface and a second surface located on the opposite side of the first surface, the second surface being provided with a recess; an epitaxial layer made of gallium oxide provided on the first surface of the semiconductor substrate; an anode electrode provided at a position overlapping the recess when viewed in the stacking direction and in schottky contact with the epitaxial layer; and a cathode electrode provided in the recess of the semiconductor substrate and in ohmic contact with the semiconductor substrate.
Further, an electronic circuit according to the present invention includes: a circuit substrate having an electrode pattern; the schottky barrier diode mounted on the circuit board; and a conductive member at least partially embedded in the recess of the semiconductor substrate and connecting the electrode pattern and the cathode electrode.
According to the present invention, since the semiconductor substrate made of gallium oxide is provided with the concave portion, the thickness of the portion through which the forward current flows can be selectively reduced. This reduces heat generation and improves heat dissipation while ensuring mechanical strength and workability. Therefore, even if gallium oxide having low thermal conductivity is used, the temperature rise of the element can be suppressed.
In the present invention, it is preferable that the recess of the semiconductor substrate includes: a bottom surface overlapping the first surface in a plan view; and an inner wall surface connecting the bottom surface and the second surface, wherein the cathode electrode is formed on at least the bottom surface of the recess. This can minimize the circuit path of the forward current, and further reduce heat generation.
In this case, the cathode electrode may be further formed on the inner wall surface of the recess, or may be further formed on the second surface located outside the recess. This improves the wettability of the solder during mounting, thereby improving mounting reliability.
In the present invention, the area of the recess portion as viewed in the stacking direction is smaller than the area of the anode electrode. Accordingly, heat generation by the forward current can be reduced, and a decrease in mechanical strength due to the formation of the concave portion can be minimized. In this case, it is preferable that the area of the recess as viewed in the stacking direction is 50% or more of the area of the anode electrode. Accordingly, heat dissipation can be sufficiently improved.
In the present invention, it is preferable that the thickness of the semiconductor substrate at the position where the recess is formed is 50 μm or more. Accordingly, since a certain degree of mechanical strength is secured also at the portion where the recess is formed, even in the case where, for example, the anode electrode is wire-bonded, the semiconductor substrate is less likely to be damaged.
In the present invention, it is preferable that the concave portion communicates with a side surface of the semiconductor substrate. Accordingly, when the solder is embedded in the concave portion at the time of mounting, air occupying the concave portion is discharged to the outside, and therefore an air layer is not formed in the concave portion. Therefore, the air layer no longer hinders heat dissipation. In this case, a plurality of the concave portions may be formed in a slit shape, or may be formed in a mesh shape.
Effects of the invention
As described above, according to the present invention, heat dissipation can be improved while suppressing heat generation while ensuring mechanical strength and operability of a schottky barrier diode using gallium oxide. This can suppress the temperature rise of the element even when gallium oxide having low thermal conductivity is used.
Drawings
Fig. 1 is a cross-sectional view showing the structure of a schottky barrier diode 10A according to a first embodiment of the present invention.
Fig. 2 is a top view of the schottky barrier diode 10A.
Fig. 3 is a cross-sectional view showing a part of an electronic circuit 100 including a schottky barrier diode 10A.
Fig. 4 is a cross-sectional view showing the structure of a schottky barrier diode 10B according to a second embodiment of the present invention.
Fig. 5 is a plan view showing the structure of a schottky barrier diode 10C according to a third embodiment of the present invention.
Fig. 6 is a cross-sectional view showing the structure of a schottky barrier diode 10D according to a fourth embodiment of the present invention.
Fig. 7 is a bottom view of the schottky barrier diode 10D.
Fig. 8 is a bottom view showing the structure of a schottky barrier diode 10E according to a fifth embodiment of the present invention.
Detailed Description
Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
< first embodiment >
Fig. 1 is a cross-sectional view showing the structure of a schottky barrier diode 10A according to a first embodiment of the present invention. Fig. 2 is a plan view of the schottky barrier diode 10A. The cross section shown in fig. 1 corresponds tobase:Sub>A cross section along the linebase:Sub>A-base:Sub>A in fig. 2.
As shown in fig. 1, the schottky barrier diode 10A of the present embodiment includes a schottky barrier diode including gallium oxide (β -Ga) 2 O 3 ) The semiconductor substrate 20 and the epitaxial layer 30. The semiconductor substrate 20 and the epitaxial layer 30 are introduced with silicon (Si) or tin (Sn) as an n-type dopant. The concentration of the dopant of the semiconductor substrate 20 is higher than that of the epitaxial layer 30, and thus the semiconductor substrate 20 acts as n + The epitaxial layer 30 acts as a layer with n - The layer functions.
The semiconductor substrate 20 is obtained by cutting a bulk crystal formed by a melt growth method or the like, and the thickness (height in the Z direction) thereof is preferably at least 50 μm or more, and particularly preferably about 250 μm. This is because when the thickness of the semiconductor substrate 20 is less than 50 μm, the mechanical strength is insufficient, and handling of the element at the time of manufacture and at the time of mounting becomes difficult. On the other hand, if the thickness of the semiconductor substrate 20 is about 250 μm, sufficient mechanical strength and workability can be secured. The planar size of the semiconductor substrate 20 is not particularly limited, but is generally selected according to the amount of current flowing into the element, and if the maximum amount of current in the forward direction is about 20A, the width in the X direction and the width in the Y direction may be about 2.4 mm.
The semiconductor substrate 20 includes: a first surface 21 located on the upper surface side when mounted; and a second surface 22 located on the opposite side of the first surface 21 and located on the lower surface side when mounted. An epitaxial layer 30 is formed on the entire first surface 21. The epitaxial layer 30 is a thin film obtained by epitaxially growing gallium oxide on the first surface 21 of the semiconductor substrate 20 by reactive sputtering, PLD method, MBE method, MOCVD method, HVPE method, or the like, and functions as a drift layer. The thickness of the epitaxial layer 30 is not particularly limited, and is generally selected in accordance with the reverse breakdown voltage of the device, and may be, for example, about 7 μm in order to secure a breakdown voltage of about 600V.
As shown in fig. 1 and 2, a recess 23 is formed in the second surface 22 of the semiconductor substrate 20, and the thickness of the semiconductor substrate 20 is selectively reduced in this portion. In the present embodiment, the shape of the recess 23 as viewed from the Z direction is circular, but the shape of the recess 23 is not limited thereto. The recess 23 can be formed by, for example, BCl from the second surface 22 side 3 And the like, by performing anisotropic etching of the semiconductor substrate 20. In the example shown in fig. 1, the bottom surface 24 of the recess 23 forms an XY plane parallel to the first surface 21, and the inner wall surface 25 of the recess 23 forms a curved surface parallel to the Z direction. However, the bottom surface 24 need not be perfectly parallel to the first surface 21, and may be a surface overlapping the first surface 21 in a plan view. Therefore, the bottom surface 24 may have an inclination with respect to the XY plane or may be curved. The inner wall surface 25 does not need to be a perpendicular surface perfectly parallel to the Z direction, and may be a surface connecting the bottom surface 24 and the second surface 22. Therefore, the inner wall surface 25 may have an inclination with respect to the Z direction.
The depth D and the diameter W of the recess 23 are not particularly limited, and when the thickness of the semiconductor substrate 20 is 250 μm, the depth D may be about 50 to 225 μm, and the diameter W may be about 100 to 200 μm. In addition, the depth D is preferably set so that the thickness of the semiconductor substrate 20 at the position where the recess 23 is formed, that is, the distance in the Z direction between the first surface 21 and the bottom surface 24 is 50 μm or more. This is because, if the thickness of the semiconductor substrate 20 at this position is less than 50 μm, the mechanical strength of this portion is insufficient, and there is a possibility that the semiconductor substrate 20 may be damaged at the time of wire bonding or the like. On the other hand, when the depth D of the concave portion 23 is too small, the heat generation suppressing effect and the heat dissipating effect cannot be sufficiently obtained, and therefore, the thickness of the semiconductor substrate 20 at the position where the concave portion 23 is formed is preferably 100 μm or less.
As shown in fig. 1, an insulating film 31 having an opening 32 is formed on the upper surface of the epitaxial layer 30, and an anode electrode 40 is formed thereon. Thereby, the anode electrode 40 is in schottky contact with the epitaxial layer 30 through the opening 32 of the insulating film 31. The insulating film 31 is made of, for example, silicon oxide (SiO) 2 ) The film thickness is about 300 nm. The anode electrode 40 is formed of, for example, a laminated film of platinum (Pt), titanium (Ti), and gold (Au), and has a platinum layer thickness of about 150nm, a titanium layer thickness of about 5nm, and a gold layer thickness of about 230 nm.
As shown in fig. 1 and 2, the anode electrode 40 is provided at a position overlapping the concave portion 23 in a plan view (viewed from the Z direction which is the stacking direction). In particular, the XY area of the concave portion 23 is preferably smaller than the XY area of the anode electrode 40 so that the entire concave portion 23 overlaps with the anode electrode 40 in a plan view. However, when the XY area of the concave portion 23 is too small, the heat dissipation effect described later becomes insufficient, and therefore, the XY area of the concave portion 23 is preferably 50% or more of the XY area of the anode electrode 40.
On the other hand, a cathode electrode 50 is provided on the second surface 22 of the semiconductor substrate 20. In the present embodiment, the cathode electrode 50 is formed on the bottom surface 24 of the concave portion 23 and the second surface 22 located outside the concave portion 23, both of which are in ohmic contact with the semiconductor substrate 20. In the present invention, the cathode electrode 50 is not necessarily formed outside the recess 23, but if considering connection reliability at the time of mounting on a circuit board, wettability of solder, and the like, it is preferable to form the cathode electrode 50 outside the recess 23 as shown in fig. 1.
According to the above configuration, the anode electrode 40 and the cathode electrode 50 are opposed to each other in the Z direction via the epitaxial layer 30 and the semiconductor substrate 20 having the concave portion 23. Therefore, if a forward voltage is applied between the anode 40 and the cathode 50, a forward current flows through the thinned portion due to the recess 23. That is, compared with the case where the recess 23 is not formed, the current path between the anode 40 and the cathode 50 is shortened, and heat generation due to the resistance component of gallium oxide can be reduced. Further, the thinned portion of the semiconductor substrate 20 is only the recess 23, and has a sufficient thickness outside the recess 23, so that the mechanical strength and workability of the semiconductor substrate 20 can be ensured.
Fig. 3 is a cross-sectional view of a part of an electronic circuit 100 including the schottky barrier diode 10A according to the present embodiment.
The electronic circuit 100 shown in fig. 3 comprises: a circuit substrate 60 having an electrode pattern 61; and a schottky barrier diode 10A mounted on the circuit substrate 60. The anode electrode 40 of the schottky barrier diode 10A is connected to another electrode pattern not shown by a bonding wire 62, and the cathode electrode 50 of the schottky barrier diode 10A is connected to the electrode pattern 61 by a solder 63.
As shown in fig. 3, a part of the solder 63 is embedded in the concave portion 23 provided in the semiconductor substrate 20. Thereby, the cathode electrode 50 formed on the bottom surface 24 of the recess 23 and the electrode pattern 61 are electrically connected by the solder 63. Since the solder 63 has a very high thermal conductivity as compared with the semiconductor substrate 20 made of gallium oxide, the heat generated by the forward current flowing through the schottky barrier diode 10A is efficiently dissipated to the circuit substrate 60 side by the solder 63 embedded in the concave portion 23. Therefore, high heat dissipation can be ensured even if gallium oxide having low thermal conductivity is used as the material of the semiconductor substrate 20. The conductive member connecting the cathode electrode 50 and the electrode pattern 61 is not limited to solder, and other conductive materials may be used.
As described above, in the schottky barrier diode 10A according to the present embodiment, since the semiconductor substrate 20 is selectively thinned at the portion where the recess 23 is formed, heat generation can be suppressed while ensuring mechanical strength and operability, and a good heat radiation characteristic can be obtained. Therefore, the switching element can be suitably used as a switching element for a power device.
Other embodiments of the present invention will be described below.
< second embodiment >
Fig. 4 is a sectional view showing the structure of a schottky barrier diode 10B according to a second embodiment of the present invention.
As shown in fig. 4, the schottky barrier diode 10B according to the second embodiment of the present invention is different from the schottky barrier diode 10A according to the first embodiment described above in that a cathode electrode 50 is also formed on the inner wall surface 25 of the recess 23. The other structure is the same as that of the schottky barrier diode 10A of the first embodiment, and therefore the same elements are denoted by the same reference numerals, and redundant description is omitted.
In the present embodiment, since the cathode electrode 50 is also formed on the inner wall surface 25 of the recess 23, the ohmic contact area between the semiconductor substrate 20 and the cathode electrode 50 can be increased. Further, the wettability of the solder 63 embedded in the concave portion 23 is improved by the cathode electrode 50 formed on the inner wall surface 25 of the concave portion 23, and the connection reliability is improved.
< third embodiment >
Fig. 5 is a plan view showing the structure of a schottky barrier diode 10C according to a third embodiment of the present invention.
As shown in fig. 5, a schottky barrier diode 10C according to a third embodiment of the present invention is different from the schottky barrier diode 10A according to the first embodiment described above in that a communicating hole 23a for connecting a concave portion 23 to a side surface of a semiconductor substrate 20 is provided in the semiconductor substrate 20. Since the other structures are the same as those of the schottky barrier diode 10A of the first embodiment, the same elements are denoted by the same reference numerals, and redundant description thereof is omitted.
In the example shown in fig. 5, 4 through holes 23a are provided, and the recess 23 is connected to the XZ side and YZ side of the semiconductor substrate. Thus, when the solder 63 is embedded in the concave portion 23 when the circuit board 60 is mounted, air occupying the concave portion 23 is discharged to the outside through the communication hole 23 a. As a result, no air layer is formed in the recess 23, and thus heat dissipation is not inhibited by the air layer.
< fourth embodiment >
Fig. 6 is a cross-sectional view showing the structure of a schottky barrier diode 10D according to a fourth embodiment of the present invention. Fig. 7 is a bottom view of the semiconductor substrate 20 used in the present embodiment, as viewed from the second surface 22 side.
As shown in fig. 6 and 7, a schottky barrier diode 10D according to a fourth embodiment of the present invention is different from the schottky barrier diode 10A according to the first embodiment described above in that a plurality of concave portions 23 are formed in a slit shape. Since the other structures are the same as those of the schottky barrier diode 10A of the first embodiment, the same elements are denoted by the same reference numerals, and redundant description thereof is omitted.
In the present embodiment, the recess 23 is formed by 6 slits extending in the Y direction. If the recess 23 is formed in such a shape, the mechanical strength of the semiconductor substrate 20 can be improved as compared with the first embodiment, and an air layer is not formed in the recess 23 when the circuit board 60 is mounted using the solder 63 as in the third embodiment.
< fifth embodiment >
Fig. 8 is a bottom view showing the structure of a schottky barrier diode 10E according to a fifth embodiment of the present invention.
As shown in fig. 8, a schottky barrier diode 10E according to a fifth embodiment of the present invention is different from the schottky barrier diode 10A according to the first embodiment in that the concave portions 23 are formed in a mesh shape. The other structure is the same as that of the schottky barrier diode 10A of the first embodiment, and therefore the same elements are denoted by the same reference numerals, and redundant description is omitted.
In the present embodiment, the concave portion 23 is formed by 6 slits extending in the X direction and 6 slits extending in the Y direction, and the concave portion 23 is formed in a mesh shape in a plan view by intersecting them. If the concave portion 23 is formed in such a shape, the mechanical strength of the semiconductor substrate 20 can be improved as compared with the first embodiment, and it is more difficult to form an air layer in the concave portion 23 as compared with the fifth embodiment.
While the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.
Examples
Assuming a simulation model having the same configuration as that of the electronic circuit 100 shown in fig. 3, the element temperature was simulated by using Au as the material of the anode electrode 40 and the cathode electrode 50 and by variously changing the depth D and the diameter W of the concave portion 23. The recess 23 has a square shape in plan view. In the simulation model, the dimensions of the semiconductor substrate 20 were X =2.4mm, Y =2.4mm, and Z =250 μm, and the dimensions of the anode electrode 40 were X =2.1mm, Y =2.1mm, and Z =0.3 μm. The solder 63 fills the entirety of the concave portion 23, and has a thickness of 50 μm from the second surface 22 located outside the concave portion 23. Then, the temperature of the center position of the anode electrode 40 was simulated assuming that a forward current was flowing from the anode electrode 40 to the cathode electrode 50 so that the cold plate corresponding to the circuit board 60 was maintained at 25 ℃ and the power consumption was 2.4W.
The simulation results are shown in table 1.
[ Table 1]
Figure BDA0002052631300000091
As shown in table 1, the temperature was raised to 54.9 ℃ in the case where the semiconductor substrate 20 was not provided with the concave portion 23, and was suppressed to 50 ℃ or lower in the case where the semiconductor substrate 20 was provided with the concave portion 23. In particular, when the depth D of the concave portion 23 was 200 μm or more, the temperature was suppressed to about 40 ℃ or less, and it was confirmed that a very high heat radiation effect was obtained.
Further, the larger the depth D of the concave portion 23, the lower the element temperature, but no large difference was seen between the case of D =200 μm and the case of D =225 μm. On the other hand, when D =225 μm, the thickness of the semiconductor substrate 20 is as thin as 25 μm, and the mechanical strength may be insufficient. If this is taken into account, D =200 μm can be considered more advantageous.
Regarding the width W of the concave portion 23, the area of the concave portion 23 when W =1mm is about 23% of the anode electrode 40, and the area of the concave portion 23 when W =2mm is about 91% of the anode electrode 40. The simulation results of the two showed no large difference, and when the width W of the concave portion 23 was large, the element temperature was lower.
Description of the reference numerals
10A-10E Schottky barrier diode
20. Semiconductor substrate
21. First surface
22. Second surface
23. Concave part
23a communication hole
24. Bottom surface
25. Inner wall surface
30. Epitaxial layer
31. Insulating film
32. Opening part
40. Anode electrode
50. Cathode electrode
60. Circuit board
61. Electrode pattern
62. Bonding wire
63. Solder
100. Electronic circuit

Claims (14)

1. A schottky barrier diode, comprising:
a semiconductor substrate made of gallium oxide, having a first surface extending in a first direction and a second direction orthogonal to the first direction, a second surface located on the opposite side of the first surface, and a first side surface extending in the second direction and a third direction orthogonal to the first direction and the second direction, the second surface side being provided with a recess;
an epitaxial layer composed of gallium oxide disposed on the first surface of the semiconductor substrate;
an anode electrode provided at a position overlapping the recess when viewed from the third direction, and in schottky contact with the epitaxial layer; and
a cathode electrode provided in the recess of the semiconductor substrate in ohmic contact with the semiconductor substrate,
the shape of the recess as seen from the third direction is circular,
the semiconductor substrate further has a first through-hole extending in the first direction and connecting the recess with the first side surface,
a width in the second direction of the first communication hole is narrower than a width in the second direction of the recess.
2. The schottky barrier diode of claim 1, wherein:
the recess of the semiconductor substrate includes: a bottom surface overlapping the first surface in a plan view; and an inner wall surface connecting the bottom surface and the second surface,
the cathode electrode is formed on at least the bottom surface of the recess.
3. The schottky barrier diode of claim 2, wherein:
the cathode electrode is also formed on the inner wall surface of the recess.
4. The schottky barrier diode of claim 2 wherein:
the cathode electrode is also formed on the second surface outside the recess.
5. The schottky barrier diode of claim 3 wherein:
the cathode electrode is also formed on the second surface outside the recess.
6. The schottky barrier diode as described in any one of claims 2 to 5, wherein:
the area of the concave portion as viewed from the third direction is smaller than the area of the anode electrode.
7. The schottky barrier diode as described in claim 6, wherein:
the area of the concave portion viewed from the third direction is 50% or more of the area of the anode electrode.
8. The Schottky barrier diode as claimed in any one of claims 1 to 5, wherein:
the thickness of the semiconductor substrate at the position where the recess is formed is 50 μm or more.
9. The schottky barrier diode as described in claim 6, wherein:
the thickness of the semiconductor substrate at the position where the recess is formed is 50 μm or more.
10. The schottky barrier diode of claim 7 wherein:
the thickness of the semiconductor substrate at the position where the recess is formed is 50 μm or more.
11. The schottky barrier diode of claim 1 wherein:
the semiconductor substrate further includes a second side surface extending in the first direction and the third direction, and a second communication hole extending in the second direction and connecting the concave portion and the second side surface,
a width of the second communication hole in the first direction is narrower than a width of the recess in the first direction.
12. The schottky barrier diode of claim 11, wherein:
the semiconductor substrate further includes a third side surface located on an opposite side of the first side surface, and a third communication hole extending in the first direction and connecting the recess to the third side surface,
a width of the third communication hole in the second direction is narrower than a width of the recess in the second direction.
13. The schottky barrier diode of claim 12 wherein:
the semiconductor substrate further includes a fourth side surface located on an opposite side of the second side surface, and a fourth communication hole extending in the second direction and connecting the concave portion and the fourth side surface,
a width of the fourth communication hole in the first direction is narrower than a width of the recess in the first direction.
14. An electronic circuit, comprising:
a circuit substrate having an electrode pattern;
the schottky barrier diode of any one of claims 1 to 13 loaded on the circuit substrate; and
and a conductive member at least partially embedded in the recess of the semiconductor substrate and connecting the electrode pattern and the cathode electrode.
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